El Niño takes its toll on penguins

El Niño and La Niña events have reduced the population of Galapagos penguins by half since 1970

By Environmental News Network staff

(ENN) -- Add the Galapagos penguin to the steadily growing list of
species whose numbers have significantly declined because of
El Niño-related events.

The increasing number and strength of warm-water El Niño
events, along with a decline of colder-water La Niña events,
have reduced the population of Galapagos penguins by half
since 1970, says researcher Dee Boersma, a University of
Washington zoology professor and a leading authority on
temperate- and equatorial-zone penguins.

Boersma just returned from the Galapagos Islands off of Ecuador in South America.
There to examine the impacts of the current El Niño, she
discovered dead marine iguanas and sea lions, undernourished
flightless cormorants and a generally emaciated penguin
population in which no juveniles were seen.

"What that suggests is that none of the penguins bred in the
last six months, or if they did breed none of (the chicks)
survived to become adults," she says.

In the equatorial Pacific Ocean surrounding the islands, Boersma
measured water temperatures of 83 to 84 degrees Fahrenheit,
which are much warmer than usual and too warm to
sustain the food supply for animals that normally feed in
the water.

"The islands were very lush, green and verdant, which is
unusual," Boersma said. "It's like the ocean is the desert
right now and the land is the garden. It's usually the other
way around."

Numbers dwindling

Boersma also discovered the impact of El Niño on marine iguanas in the Galapagos Islands

Boersma is concerned that the increased intensity and
frequency of El Niño events, combined with fewer and milder
La Nina events, could continue reducing the islands' penguin
population.

"I'm certainly not at all convinced that the Galapagos
penguin is going to go extinct because of this," Boersma
said. "But I am concerned that the numbers are going to
become increasingly low, and we know that with smaller
populations they're just more vulnerable to extinction."

The flightless birds typically stand 20 to 24 inches high
and weigh 4 to 5 pounds. They live primarily on two islands
in the Galapagos Archipelago off the coast of Ecuador. Since
they can range to the northernmost reaches of the chain,
above the equator, they are the only penguins whose natural
habitat is in the Northern Hemisphere.

Boersma says the birds' current population is likely in a
range of 4,250 to 8,500, half the total when she first
studied their population and nesting patterns in the early
1970s.

There are two primary reasons for the population decline,
both linked to food shortages because of El Niño, Boersma
says. In some instances, adults simply don't attempt to lay
eggs. In other cases, they don't have enough food to sustain
themselves and so they abandon their nests.

The situation is complicated further by increasing human
activity in the islands. More boats increase the likelihood
of oil dumping, Boersma says, and a larger number of people
engaged in fishing make it more likely for penguins to get
caught in the nets.

However, the Galapagos are protected by a 50-mile protection
zone and there is great care taken to keep human impacts in
the area down to a minimum.

The penguins' sharpest population decline appears to have
come during the El Niño of 1982-83, the strongest recorded
before the current El Niño started.